It feels like this anime has combined two different genres into one great adventure. First, you got that adventure vibe in the first half, the epic quest as I would call it. The action's intense and rewarding, stakes are high, great villain, and finally, that mind game.
Then, we come to the second half! A half slice of life and a half mystery. The characters who used to be villains now join up with the good guys. One of the good guys becomes the "speculated mastermind villain". Now, there's romance in the plot! While all this is happening, they all have the combined goal to defeat the true villain.
That's my short, unspoiled review of this journey. You really have to watch this anime, I can't make this any longer because I don't want to accidentally spoil any watchers...